• Current Optics and Photonics
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• v.7 no.5
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• pp.529-536
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• 2023

The Morlet wavelet transform method is proposed to analyze a single interferogram with spatial carrier frequency that is captured by an optical interferometer. The method can retain low frequency components that contain the phase information of a measured optical surface, and remove high frequency disturbances by wavelet decomposition and reconstruction. The key to retrieving the phases from the low-frequency wavelet components is to extract wavelet ridges by calculating the maximum value of the wavelet transform amplitude. Afterwards, the wrapped phases can be accurately solved by multiple iterative calculations on wavelet ridges. Finally, we can reconstruct the wave-front of the measured optical element by applying two-dimensional discrete cosine transform to those wrapped phases. Morlet wavelet transform does not need to remove the spatial carrier frequency components manually in the processing of interferogram analysis, but the step is necessary in the Fourier transform algorithm. So, the Morlet wavelet simplifies the process of the analysis of interference fringe patterns compared to Fourier transform. Consequently, wavelet transform is more suitable for automated programming analysis of interference fringes and avoiding the introduction of additional errors compared with Fourier transform.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.464-466
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• 2009

This study tried to examine the suitability of strip casting process such as PFC (Planar Flow Casting) method for soldering Au-Sn strip. The effect of heat treatment on the tensile behavior and mechanical properties of an Au-Sn strip was investigated through tensile test, micro hardness test, X-ray diffraction (XRD), SEM, and TEM observations. It was apparent that 20-mm width Au-Sn strip could be well produced by using planar flow casting process. Tensile results showed that tensile strength increased from 338.3MPa to 310MPa and plastic strain improved from 0% to 1.5% with heat treatment ($170^{\circ}C$/70 hrs.). The microstructure of Au-Sn strip mainly consisted of two phases; $Au_5Sn(\zeta)$ and AuSn($\sigma$). It was also found that inhomogeneous amorphous local structure continuously changed to the homogeneous two phases microstructure with heat treatment. The fractographical observation after tensile test indicated the cleavage fracture mode of as-casted Au-Sn strip. On the other hand, the heat treated Au-Sn strip showed that fracture propagated along interface between brittle AuSn and ductile $Au_5Sn$ phases. The deformation behavior of strip casted Au-Sn alloy with microstructural evolution and the improve method for ductility of this alloy was also suggested.

• Journal of the Korean School Mathematics Society
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• v.20 no.2
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• pp.91-117
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• 2017

In this paper, we develop a logarithm units' teaching learning materials using genetic modeling which is designed for students to construct by themselves and figure out mathematical knowledge conceptually, and we analyze the process of students' comprehension of logarithm concepts through genetic modeling activities. For this purpose, we divide logarithm units into three subunits and develop teaching learning materials which include genetic original contexts and are framed by the four pedagogic phases of genetic modeling, application, extraction, comprehension, and construction so that students themselves are capable of construct the concepts of logarithm units. The developed teaching learning materials are applied into lessons for two intermediate-basic students and two intermediate-advanced students. Through this, we examine students' conceptual construction process about logarithms units with the four pedagogical stages of genetic modeling applied, and analyze the depth of their comprehension about the logarithm units based on the general phases of mathematics-learning introduced by van Hiele, and then we suggest several pedagogical implications.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.188-188
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• 2003

• 전기의세계
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• v.28 no.8
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• pp.34-44
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• 1979

The article is organized as follows: In Section 2, the functions involved in the total design process are discussed in terms of five phases and the term IGCAD (interactive graphic computer aided design) is introduced. Section 3 is devoted to the discussion of the IGCAD system and turns out to be the longest section. We discuss two particular examples of IGCAD applications and the benefits of IGCAD methodology in Section 4.

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1132-1134
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• 2005

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.10a
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• pp.53-56
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• 1984

This paper shows that the error probabilities for coherent and noncoherent BF나 systems combined with FH in the presence of single channel tone interference. The performance is developed as functions of the signal to noise ratio and jamming to noise ratio. A specific results for two phases of ㅠ/4 and ㅠ/2 is obtained.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.583-588
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• 1995

Fe rich nanocrystals embedded in an amorphous magnetic matrix have been shown to exhibit outstanding soft magnetic properties. The cause of softness in the exchange coupling between the two-phases. In this paper some effects of the exchange coupling between the nanocrystals and the matrix are reviewed.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1117-1124
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• 2011

An integrated fault detection and isolation method is proposed in this paper. The main objective of this paper is development fault detection, isolation and diagnosis algorithm based on the DKF (Decentralized Kalman Filter) and the bank of IMM (Interacting Multiple Model) filters using penalty scalar for both partial and total faults and the outlier detection algorithm for preventing false alarm also included. The proposed FDI (Fault Detection and Isolation) scheme is developed in four phases. In the first phase, the outlier detection filter is designed to prevent false alarm as a pre-filter. In the second phases, two local filters and master filter are designed to detect sensor faults. In the third phases, the proposed FDI scheme checks sensor residual to isolate sensor faults and 11 EKFs actuator fault models are designed to detect wherever actuator faults occur. In the last phases, four filters are designed to identify the fault type which is either the total fault or partial fault. The developed scheme can deal with not only sensor and actuator faults, but also preventing false alarm. An important feature of the proposed FDI scheme can decreases fault isolation time and figure out not only fault detection and isolation but also fault type identification. To verify the proposed FDI algorithm performance, the Simulator is also developed under the Matlab/Simulink environment.

• Journal of KIBIM
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• v.8 no.2
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• pp.41-50
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• 2018

The current study focused on the utilization of building information modeling (BIM) data in steel-frame structures, which help to reduce project durations because they employ prefabricated structural members that are assembled on-site. In addition, a business process model was proposed using BIM data collected during the preconstruction, structural steel fabrication, and on-site construction phases of an actual steel-frame project. The ultimate expectation is that BIM data support at each phase, as well as the increased understanding among project participants, will result in an increase in project management productivity. The results from the current study are summarized as follows: To implement a BIM capable of application to steel-frame projects and data utilization, existing theories were studied to develop the construction project steps, both generally into the preconstruction (A1), steel fabrication (A2), and on-site construction phases, (A3) and specifically into 19 BIM-applicable phases. Based on the derived BIM-applicable phases, the model elements of the BIM object were identified, and the shortcomings of existing steel-frame projects were ameliorated, resulting in an improved data flow model. Moreover, for the proposed BIM data flow to progress efficiently, the BIM specialist needs to be well-acquainted with the phase-specific three-dimensional (3D) model output, and the infrastructure to construct an error-free 3D model must be provided. Based on the actual construction example, the BIM data utilized steel-frame projects - via production reports, clash checks, two-dimensional (2D) drawings, four-dimensional (4D) simulations, and 3D scanning - to make cooperation and communication among participants easier.